This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project is focused on determining the structure of the YaeT protein, which is the central component of the YaeT complex responsible for insertion of proteins in the bacterial outer membrane. Interfering with this mechanism of Outer Membrane Protein insertion would be an effective strategy for antibiotic development;much like beta-lactams are effective by inhibiting cell wall synthesis. YaeT consists of a C-terminal beta-barrel embedded in the outer membrane, and an N-terminal periplasmic domain containing five copies of so-called POTRA (polypeptide-transport-associated) sequence motifs. We have determined the crystal structure of a periplasmic YaeT fragment containing 4 POTRA domains.